All Blacks and Crusaders lock Sam Whitelock has been ruled out of rugby for at least four weeks after he fractured a finger in his team's 28-19 Super Rugby loss to the Chiefs at Waikato Stadium on Friday night.

All Blacks head coach Steve Hansen confirmed the 24-year-old would be absent for as long as six weeks after breaking his right ring finger, meaning he was likely to miss the three-match Test series against France.

"Sam will undergo a follow-up x-ray after which we should have a clearer picture of the injury and what that means for his return to rugby," Hansen said.

"While this is disappointing for Sam, and for the All Blacks, one man's misfortune is another man's opportunity, so we look forward to seeing that opportunity being realised."

The first Test against France is on June 8 in Auckland, followed by matches in Christchurch and New Plymouth.